Need info on doing swap?

I am in the process of doing the same thing and let me tell you, it takes some time and money. The cheapest way would be to buy a complete TPI engine out of a junkyard, with the wire harness. As I found out, it is hard to find a complete engine with a harness, at least a speed density 350 TPI. As far as what you would need to make the swap, check out the Tech articles, they have an article on a TBI to speed density TPI. GM parts direct would be a good place to start if you know what you need and have the GM part numbers.

You will have to give some more detail on what you have already and what you want out of your TPI. Do you just want the stock setup or are you wanting more even more HP than the stock TPI?

Well I would obviously want more Power, thats for sure. A Buddy of mine told me to grab the mass air flow off the corvette cause it draws way more power. what about exhaust? Do the 305 manifols bolt up, or no?

Another thing, I was wondering. Younotice how the 350 T.P.I over the years from when it was raleased the HP & Torque numbers were rising. Is that due to actual engine modifications made by GM, or is it all electrical / computer mods?

Casue when I do go to buy, if it is motor, i would grab a newer one or vice - versa?

The only thing that I do know is that the 1985-89 used the mass airflow (MAF) sensor to measure the amount of air entering the engine. The sensor is located in the intake hose before the throttle body and is very expensive to replace. These engines also have a 9th injector for cold starts.

1990-1992 TPI engines used a manifold absolute pressure (MAP) sensor to determine load. Most people like these speed density systems, this is the system that I will be using.

As for power difference between the Corvette and Camaro/Firebird, I believe the only difference was that the Corvette has a much better exhaust system, which gave them a better HP rating.

In the Tech section on this webpage it will show you the HP and Torque ratings for the different years of Camaros and Firebirds, it also will tell you the difference in camshafts that were used, they have changed through the years.

Your exhaust manifolds should bolt upto a TPI, but I would suggest some headers. If you want to continue using the emissions Edelbrock and SLP make headers for your application. Edelbrock only makes a 1 5/8" header, where SLP makes a 1 5/8" and a 1 3/4" header, SLP alos makes headers for single and dual exhaust and the best thing is that they are made of stainless steel. If you are not worried about emissions or need a CAT, then people use all kinds of different headers on this board.

TPI engines are great Torque monsters, but are not high reaving high horse paower engines. If you want more HP than a stock TPI, then you will need to look at replacing your intake, runners, porting the Plenum and going to a larger throttle body, of course none of this will matter if you leave that stock cam in the car. GM, TPIS, and Competition Cams make some great replacement Hydrolic Roller cams that will increase your HP.

Head selection is another good place to increase HP. GM Votec, GM fastburn, Trick Flow, Edelbrock, and AFR are what most people use. Just do a search for what others have to say. I am using the Air Flow Research Heads, they are unbelievable (they will break the bank, but well worth the money).

I hope that I have helped and that I did not bore you with information that you already know. I should be ready by the end of january to do my TBI to TPI swap and can't wait. I have a 350 four bolt main one piece rear main seal block, GM PM conecting rods, Nodular Iron Crank, Forged TRW pistons, LT4 Hotcam, 1.6 ratio GM roller rockers, AFR 190 heads, SLP 1 3/4" headers, Edelbrock ported base, SLP ported runners, Ported Plenum and siamesed to match the SLP runners, 52mm Throttle Body, along with the mods in my signiture, it should be a fun car to drive. Anyway good luck with your project.

Thanks Dude, you did help me alot.

So How much did it cost you in total for the peromance ad-ons for the motor.

Actually, 1 more question. A Buddy of mine told me to just grab the motor & the computer & get the wiring harness from that company, umm whats it called? The one that sells all the wiring harness, there always talked about on Horsepower TV & stuff?

Anwyays, thanks alot man, you have been a huge help.

Merry Christmas.

Hey man, its me again. I was reding your info, Does that Hypertech Chip make any difference in power, liek is noticable?

I think that you are talking about a Painless wire harness, they work great for street rods when installing a TPI. But from what I have read on this board is that they are a pain to use. Not all of the connections are there and the length is not right for our swap. If you feel comfortable with wiring and adding lenghts and connection, the price is very reasonable, around $280. Street and Performance makes a integrated harness to go from a TBI to TPI, but it cost close to $600, You can still get one from GM, but they are around $550 from GM parts Direct. I would look on ebay are check junk yards, although it is very hard to find a Speed Density harness, trust me I looked for 6 months.

As far as the Hypertech Chip, I did notice a little difference, but I do not know if was worth the price. For my TPI setup, I will probable have have a custom chip made by Ed Wright at Fastchip, most people on this board will tell you to burn your own chip, it is around $300 for the equipment. There is a good tech article on this process also.

As for the price of add ons, it will very depending on where you buy them. Summit is a good place to start, they sell SLP products, Accel, BBK, Edelbrock. TPIS is another place that sells alot of TPI products, and Arizona Speed and Marine. All of the places mentioned have web sites, here are the addresses:

Street and Performance-www.hotrodlane.cc
Arizona Speed and Marine-www.azspeed-marine.com
GM parts direct-www.gmpartsdirect.com
SLP-www.slponline.com
TPIspecialist-www.tpis.com
Summit-www.summitracing.com
Air Flow Research-www.airflowresearch.com

These sites should help and I would suggest searching topics on this website, it will save you time and money in the long run. Cause I would say that most every combination has been tried and you can see what did and did not work for other people.

why do you want TPI? with some tuning and a $100 carb intake + TBI adapter plate you can run low 13s easy.

i did the tbi 2 tpi swap on my 89 iroc i found a intergrater harness that pluged right in no cutting or hacking from street and performance i had no problems with it and everything was labeled it was a speed densitdy system i used my original map sensor and a lot of other stuff worked out great it was about $500 with a custom chip

If you want to do this swap and right it will take quite a bit of time. I recommend doing it slowly and collecting the basic parts. For one, get a TPI swappers book. Read it twice. Make your life much easier. Try to understand the electronics real well. Then for the hell of it a chilton's manual and look at the chassis wiring for the TPI system you want and for your car. Here's the big one, you'll need the fuel pump and lines for a TPI system, the TBI will not work. I think it would be easier just to rip off the entire gas tank to avoid any further confusion with trying to install the the TPI pump on your TBI one. Then you'll probably need to get the dual fan setup for your front out of the TPI. The TBI's only have a single fan and really isn't suffiencient for cooling it. Other then that, DON'T get a painless wiring harness. You'll have more problems most likely. Pull your own harness out of a TPI car and the complete thing along to the ECM and try not to cut any wires. This is where you'll have your problems. Most likely some fuel injectors as well as sensors will be bad. Try wiring it right. Making sure your engine is good. You'll probably be happy.
SEARCH THE ARCHIVES! You'll find a ton of info and try emailing some of the people who've done it before. I haven't, but I really am getting close to doing it next summer.

Damon over on cz28.com posted that the stock tbi lines will work with a in-line pump, so you dont have to drop your tank. The stock pump works as a pickup, and the new in-line one pulls more fuel. Is it true? That would make the swap quite a bit easier...